Lead poisoning is a major pediatric disease in many large cities. Although the kidney is a well-documented target organ for lead, neither the extent nor the renal mechanisms involved in childhood plumbism have been elucidated. The proposed investigation is designed to study how the maturing kidney of young animals responds to low-level lead exposure. In this context, we intend to study the effects of lead on the maturation of a) glomerular filtration, b) renal tubular function, and c) renal hemodynamics. Several studies, primarily from Australia, have indicated that lead exposure in the early stage of life frequently results in adult nephropathy. Therefore, a second objective of this proposal is to study the extent and degree of renal damage persisting into adulthood following lead exposure of the young animal. Blood lead levels are currently the major criterion of assessing lead exposure. In most pediatric lead clinics, two successive blood lead determinations of 50 micrograms Pb/100 ml whole blood are sufficient to recommend the individual for further evaluative study (4). However, as yet, no good correlation exists between blood lead levels and observable toxic effects. Therefore, a third objective of these studies will be to determine the correlation between blood and/or kidney lead levels and the indices of renal dysfunction described in the first two objectives.